Continuous annealing and pickling unit for hot and cold rolled strip steel

The application of continuous annealing machine in hot and cold rolled strip steel

Introduction

Hot-rolled steel strip annealing and pickling machine (abbreviated as continuous annealing machine) is one of the main equipments used in hot-rolled strip processing. It is mainly used for bright annealing and pickling of hot-rolled strips in a continuous production line. The continuous annealing machine consists of an annealing furnace and a pickling device. It has the characteristics of low investment, low operation cost and high production efficiency, and is suitable for mass production.

Working principle

The working principle of the continuous annealing machine can be divided into three parts: uncoiling and feeding of the hot rolled strip, annealing and pickling, and the transport and coiling of the annealed strip. The hot-rolled strip enters the annealing and pickling furnace from the descaling box, and then moves on the conveyor with roller of the annealing and pickling machine, and passes through the annealing and pickling furnace. During the motion, the pickling acid solution sprayed by the spray system and the protective gas dedusting operation will make the surface of the hot-rolled strip reach the eutectoid temperature, and complete the annealing and pickling. After the annealing and pickling, the strip is cooled by cooling equipment in the furnace, transported and coiled by the coiler of the coiling zone, and then discharged for further rolling.

Advantages

The continuous annealing machine is an indispensable equipment for mass production of hot-rolled strips. Compared with other annealing and pickling equipments, it has the following advantages.

1. The strip is heated evenly, and the bright annealed strip has a bright and uniform surface.

2. The annealing and pickling temperature is uniform and the heating speed is fast.

3. The annealing and pickling speed is fast, and the production efficiency can reach 1000m/min.

4. Low investment, low operation cost and low unit energy consumption.

5. The surface quality of hot-rolled strips can be improved through continuous annealing and pickling, and the corrosion resistance, welding performance and appearance quality of steel products are improved.

Conclusion

With the advancement of strip steel continuous annealing technology, the continuous annealing machine has a wide application prospect in hot-rolled and cold-rolled strip steel industries. Continuous annealing machines not only reduce the energy consumption of the entire production process, but also ensure the same quality of steel strips, improve the yield of steel products and reduce the cost of production.

Continous Annealing, pickling and Skin-pass Line

Continous Annealing, Pickling line and Skin-pass Line are the ultimate complete set for hot and cold rolled strip processing. The one line provides customers with a wide variety of products from low-carbon, high-tensile steels to complex alloy grades and high-strength steels.

The continuous casting line is designed for mass production and has a production capacity of up to 180tons/hour for hot-rolled strip and up to 140tons/hour for cold-rolled strip. The line features four basic process lines, annealing furnaces, pickling tanks, skin-pass mill, and cooling bed.

The annealing furnace provides controlled atmosphere annealing of strip to maximize surface quality and strip properties. The atmospheric air is removed from the furnace to create a special atmosphere consisting mainly of nitrogen, carbon dioxide and hydrogen. By diffusing heat into the strip, the annealing furnace improves strip properties and homogeneity including softness, formability, improved surface finishing and metallurgical properties.

The pickling tanks offer highly efficient pickling of hot-rolled strip and cold-rolled strip using latest technologies. The pickling tanks are equipped with advanced environmental control equipment that ensures no discharge of pickling liquid and sludge. The pickling tanks offer highly efficient removal of scale from the surface of the strip and uniform pickling results across the width of the strip. This ensures improved surface quality and grain structure of the strip.

The main purpose of the skin-pass mill is to the last improvement of the strip surface before delivery to the customers. This includes improvement in surface texture and reduction of flow marks on the strip. The skin-pass mill also ensures improved material properties such as increased yield strength, better strip flatness and improved matt grey finish.

Finally, the cooling bed ensures a uniform cooling of the strip and uniform tension with the strip speed to ensure improved surface quality and strip properties. The cooling bed is designed for quick cooling of strip and uniform temperature across the entire width of the strip.

The complete line is designed for mass production of hot and cold rolled strip with improved strip properties and surface quality. This ensures a full range of products from low-carbon, high-tensile steels to complex alloy grades and high-strength steels.